The invention relates generally to wind deflection. More particularly, it concerns a device for smoothly redirecting wind away from the ear for the purpose of decreasing any personally heard wind noise generated by air flow past the ear and head due to changes in air pressure, while at the same time permitting ambient sound to pass through untenanted. There are two main sources of perceived wind noise. In a head wind the first source is due to the shape of the head causing turbulence just behind the cheek bone, and has a spectral content that is heavily tilted toward lower frequencies. The second source appears to be due to stream flow by the concha which is the shallow cavity inside the ear just adjacent to the sensitive ear canal, and is apparently responsible for the higher frequency noise.
At low wind speeds, the combined noise spectrum creates a personal rumbling in the ear canal which gets louder and also higher in frequency as the wind speed increases. Unweighted measurements have been made of the noise created in the concha by the use of a microphone probe apparatus. See, U. R. Kristiansen, O. K. Pettersen 1978 Journal of Sound and Vibration, “Experiments On The Noise Heard By Human Beings When Exposed To Atmospheric Winds”. For an average person facing a 21 mile per hour (mph) wind the noise spectrum was found to extend below 25 cycles per second (Hz) to about 150 Hz at an intensity of 92 decibels (db) above quiet hearing threshold. Prolonged exposure above 85 (dbA) causes slight hearing loss and hearing protection is recommended. The signal to noise ratio of speech to wind induced ear canal noise can significantly deteriorate for winds above 20 mph. This comes as no surprise to hard of hearing sufferers who have lost their high frequency sensitivity and must completely rely on the lower part of hearing spectrum. In this regard for many people with hearing loss, the tolerance for loud sound is lower than the tolerance of someone with normal hearing. Bike riders, skiers, etc. with good hearing may have considerable difficulty hearing ambient sounds such as traffic, conversations between companions, safety warnings and certain sounds of nature. High relative wind speeds are not uncommon, e.g., by cycling 15 mph into a 15 mph atmospheric wind the relative headwind is 30 mph.
There is the additional problem of fatigue. The apparent intensity of the wind seems to be greater when it can be heard. Constant and especially gusty wind noise over a long period of time can create considerable fatigue, which if not corrected can reduce the enjoyment of an activity and can turn to irritation. Worse, fatigue can also be a contributing factor in creating misjudgments and accidents.